Study on Electrophoretic Deposition Characteristics of Ultra-Fine Diamond Powder

2012 ◽  
Vol 472-475 ◽  
pp. 2702-2706 ◽  
Author(s):  
Xian Yan Mao ◽  
Jing Lu ◽  
Hua Guo
Keyword(s):  
Electrophoretic Deposition ◽  
Applied Voltage ◽  
Deposition Time ◽  
Diamond Powder ◽  
Simple Method ◽  
Wear Resistant ◽  
Suspension Concentration ◽  
Fine Diamond ◽  
Tools Wear ◽  
The Impact

Diamond is a promising material especially applied in advanced machining tools, wear-resistant coatings, and the EPD technique should provide a simple method to develop hard coatings for precision machining tools or wear-resistant parts. Therefore, it is useful to research electrophoretic deposition characteristics of diamond powder itself, including the impact of adding ions on direction of EPD especially. In this paper, the effects of suspension concentration and applied voltage, deposition time, and added Ca2+ or Al3+ ions on electrophoretic characteristics of ultra-fine diamond powder were discussed, and electrophoretic deposition (EPD) parameters were optimized by a trial-and-error approach. The results show that smooth, uniform and dense coatings of diamond were obtained under suspension concentration of 1%-1.5% and applied voltage of 30-70 V. The thickness of diamond coating can be controlled by adjusting deposition time under constant voltage and suspension concentration. If deposition direction changed, the appropriate concentration of added Ca2 + and Al3 +, respectively, is in the range of 0.005% to 0.01% and 0.05% to 0.10%.

Study of the Electrophoretic Deposition of Chitosan/Halloysite Nanotubes/Titanium Dioxide Composite Coatings Using Taguchi Experimental Design Approach

2015 ◽  
Vol 654 ◽  
pp. 230-239 ◽  
Author(s):  
Namir S. Jackoub Raddaha ◽  
Sigrid Seuss ◽  
Aldo R. Boccaccini
Keyword(s):  
Titanium Dioxide ◽  
Electrophoretic Deposition ◽  
Applied Voltage ◽  
Deposition Time ◽  
Composite Coatings ◽  
Halloysite Nanotubes ◽  
Partial Least Square ◽  
Halloysite Nanotube ◽  
Taguchi Design Of Experiments ◽  
Deposition Yield

This study presents experimental results on the electrophoretic deposition (EPD) of chitosan/halloysite nanotube/titanium dioxide composite coatings based on the Taguchi design of experiments (DOE) approach. Taguchi array of L18type with mixed levels of the control factor was used to study the influence of EPD parameters, including halloysite nanotubes concentration, electric voltage and deposition time, on deposition yield. For identifying the significant factors that affected the deposition yield, multivariate analysis of variance (MANOVA) and regression analysis based on partial least-square method were used. The coatings were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy analyses, respectively. It was found that the deposition time has significantly influenced the deposition rate but the halloysite nanotube concentration and the applied voltage have the smallest effect on the deposition. The optimum condition for high yield of deposition with low standard deviation is achieved when the concentration of halloysite nanotubes is 0.3 g/L and the applied voltage is 40 volt with 300 sec. as a deposition time. The predicted EPD conditions were verified by experiments and qualitative agreement was obtained.

Electrophoretic Deposition of Natural Hydroxyapatite

2009 ◽  
Vol 412 ◽  
pp. 183-188
Author(s):  
Mehdi Javidi ◽  
Sirus Javadpour ◽  
Mohammad Ebrahim Bahrololoom ◽  
Jan Ma
Keyword(s):  
Zeta Potential ◽  
Electrophoretic Deposition ◽  
Applied Voltage ◽  
Deposition Time ◽  
316L Stainless Steel ◽  
Deposition Process ◽  
Dispersing Agent ◽  
Coating Efficiency ◽  
The Stability ◽  
Natural Hydroxyapatite

Natural hydroxyapatite has been electrophoretically deposited on medical grade 316L stainless steel. Stable suspensions were prepared by mixing 40 g/L milled natural hydroxyapatite powder in isopropyl alcohol and stabilized by polyethylenimine as dispersing agent and binder. The stability of suspensions was investigated by measuring zeta potential. It was found here that the suspension which was stabilized with 4 g/L polyethylenimine revealed a high value of zeta potential and stability. Deposition was achieved on the cathode at constant voltages of 30, 60, and 90 V for 1 to 5 minutes. After deposition, the samples were dried at room temperature for 24 hours and deposition weight, roughness, and thickness of the coatings were measured. The surface morphology of the coated samples was studied by a scanning electron microscope. The results of the electrophoretic deposition process showed that the sample coated at 60 V and 3 minutes led to an adherent, continuous, and crack-free coating. The coating efficiency and thickness increased with increasing deposition time and yielded to saturation at the constant applied voltage. Also, the current density decreased and yielded to saturation at the constant applied voltage during electrophoretic deposition.

Different Morphology of Hydroxyapatite Coatings on Titanium by Electrophoretic Deposition

2007 ◽  
Vol 330-332 ◽  
pp. 609-612 ◽  
Author(s):  
Xian Wei Meng ◽  
Tae Yub Kwon ◽  
Kyo Han Kim
Keyword(s):  
Electrophoretic Deposition ◽  
Applied Voltage ◽  
Deposition Time ◽  
Concentration Level ◽  
Processing Parameters ◽  
Optimal Conditions ◽  
Polycrystalline Structure ◽  
Ha Coating ◽  
Hydroxyapatite Coatings

The objective of the present study was to define the optimal conditions and characterizations of hydroxyapatite (HA) coatings on titanium by electrophoretic deposition (EPD). The EPD processing parameters, such as deposition time, HA concentration level in the suspension, and applied voltage are experimentally determined. A good packing, crack-free and uniform HA coating on titanium was prepared. Then the coatings were sintered at 800 °C for 2 h. The sintered coatings presented a very homogeneous polycrystalline structure free of cracks. The results show that the application of EPD is an effective method in obtaining HA coatings with good properties.

scholarly journals Modelling, Analysis, and Optimization of the Effects of Pulsed Electrophoretic Deposition Parameters on TiO2 Films Properties Using Desirability Optimization Methodology

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5160
Author(s):  
Nesrine Barbana ◽  
Adel Ben Youssef ◽  
Mohamed Ali Rezgui ◽  
Latifa Bousselmi ◽  
Mohammad Al-Addous
Keyword(s):  
Thin Film ◽  
Response Surface ◽  
Electrophoretic Deposition ◽  
Duty Cycle ◽  
Applied Voltage ◽  
Deposition Time ◽  
Desirability Function ◽  
Quadratic Model ◽  
Adhesion Properties ◽  
Optimization Methodology

Titanium dioxide thin films immobilized over treated stainless steel were prepared using the pulsed electrophoretic deposition technique. The effects of process parameters (deposition time, applied voltage, initial concentration, and duty cycle) on photocatalytic efficiency and adhesion properties were investigated. To optimize the multiple properties of the thin film, a response surface methodology was combined with a desirability optimization methodology. Additionally, a quadratic model was established based on response surface analysis. The precision of the models was defined based on the analysis of variance (ANOVA), R2, and the normal plot of residuals. Then, a desirability function was used to optimize the multiple responses of the TiO2 thin film. The optimum values of applied voltage, catalyst concentration, duty cycle, and deposition time were 4 V, 16.34 g/L, 90% DC, and 150 s, respectively. Under these conditions, the decolorization efficiency of tested dye solution reached 82.75%. The values of critical charges LC1, LC2, and LC3 were 5.9 N, 12.5 N, and 16.7 N, respectively.

scholarly journals Assessing an Atmospheric Correction Algorithm for Time Series of Satellite-Based Water-Leaving Reflectance Using Match-Up Sites in Australian Coastal Waters

2021 ◽  
Vol 13 (10) ◽  
pp. 1927
Author(s):  
Fuqin Li ◽  
David Jupp ◽  
Thomas Schroeder ◽  
Stephen Sagar ◽  
Joshua Sixsmith ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Atmospheric Correction ◽  
Correction Method ◽  
In Situ Measurements ◽  
Landsat 8 ◽  
Correction Algorithm ◽  
Simple Method ◽  
North East ◽  
The Impact

An atmospheric correction algorithm for medium-resolution satellite data over general water surfaces (open/coastal, estuarine and inland waters) has been assessed in Australian coastal waters. In situ measurements at four match-up sites were used with 21 Landsat 8 images acquired between 2014 and 2017. Three aerosol sources (AERONET, MODIS ocean aerosol and climatology) were used to test the impact of the selection of aerosol optical depth (AOD) and Ångström coefficient on the retrieved accuracy. The initial results showed that the satellite-derived water-leaving reflectance can have good agreement with the in situ measurements, provided that the sun glint is handled effectively. Although the AERONET aerosol data performed best, the contemporary satellite-derived aerosol information from MODIS or an aerosol climatology could also be as effective, and should be assessed with further in situ measurements. Two sun glint correction strategies were assessed for their ability to remove the glint bias. The most successful one used the average of two shortwave infrared (SWIR) bands to represent sun glint and subtracted it from each band. Using this sun glint correction method, the mean all-band error of the retrieved water-leaving reflectance at the Lucinda Jetty Coastal Observatory (LJCO) in north east Australia was close to 4% and unbiased over 14 acquisitions. A persistent bias in the other strategy was likely due to the sky radiance being non-uniform for the selected images. In regard to future options for an operational sun glint correction, the simple method may be sufficient for clear skies until a physically based method has been established.

Nitrification preservation in activated sludge during curative bulking chlorination

2003 ◽  
Vol 47 (11) ◽  
pp. 85-92 ◽  
Author(s):  
E. Cotteux ◽  
P. Duchene
Keyword(s):  
Activated Sludge ◽  
Pilot Plant ◽  
Wastewater Treatment Plants ◽  
Oxygen Uptake Rate ◽  
Ammonia Concentration ◽  
Synthetic Wastewater ◽  
Biological Wastewater Treatment ◽  
Simple Method ◽  
Method Of Measurement ◽  
The Impact

The bulking that occurs in biological wastewater treatment plants using activated sludge is very often controlled by the injection of sodium hypochlorite into the return activated sludge (RAS) stream. In the present study undertaken at two pilot plants fed with synthetic wastewater, the impact of the pass frequency of the sludge at the chlorine dosing point on the nitrifying flora is analysed. The pass frequency is one for the pilot plant 1 and two for the pilot plant 2. A dose of chlorine of 4.85 ± 0.05 g/kg/MLVSS per day was applied at both pilots. The preservative effect on nitrifying activity of the lowest concentration of chlorine at the dosing point and therefore of the highest pass frequency was evidenced. Among other tools, a simple method of measurement of the oxygen uptake rate enabled us to monitor the effect of chlorination on nitrification before recording an increase in the ammonia concentration in the bulking.

Ultra-Low-Power Electrophoretic Deposition of Silica Powder with Nonflammable Organic Solvent

2015 ◽  
Vol 654 ◽  
pp. 88-93
Author(s):  
Hideyuki Negishi
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Electrophoretic Deposition ◽  
Particle Concentration ◽  
Deposition Time ◽  
Ultra Low Power ◽  
Silica Powder ◽  
Inorganic Particles ◽  
Uniform Coating ◽  
Electrical Insulation Properties

Although conventional organic solvents are used in electrophoretic deposition (EPD) owing to several advantages, they are hazardous because of their inflammability or ignition properties. In contrast, hydrofluoro ether (HFE) is nonflammable, polar and possesses excellent electrical insulation properties. In this study, methoxy-nonafluorobutane (MNFB), which is one of HFE was used as the solvent for the EPD of silica powder. Because the density of MNFB is larger than water, sedimentation of inorganic particles is slow. The deposition behavior in MNFB was similar to the EPD in conventional solvents, and was controlled by tuning the applied voltage, deposition time, and particle concentration. A uniform coating was obtained. Notably, the power consumed in this process was significantly lower than that in the EPD using conventional solvents. The current density was of the order of 10 nA/cm2; therefore, the electric power consumption for EPD using MNFB was less than 0.1% of those using conventional solvents. Therefore, MNFB can be used as an effective solvent for EPD because it is nonflammable, allows the application of high voltage, and enables the deposition of particles with low power consumption.

Electrophoretic Deposition of Titania Thin Films: Influence of Deposition Time on Microstructural and Optical Properties of the Coatings

2013 ◽  
Vol 829 ◽  
pp. 917-921
Author(s):  
Saber Ghannadi ◽  
Hossein Abdizadeh ◽  
Mohammad Reza Golobostanfard
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Electrophoretic Deposition ◽  
Deposition Time ◽  
Colloidal Suspension ◽  
Vis Spectroscopy ◽  
Titania Films ◽  
Titania Sol ◽  
Deposited Film ◽  
Deposited Films

Titania thin films were prepared by electrophoretic deposition at various deposition times (1, 5 and 10 min) in constant applied potential (5 V). For this purpose, modified titania sol was prepared as a colloidal suspension. The influence of deposition time on the thickness and optical properties of titania films was investigated. Scanning electron microscope images illustrate compact and homogeneous titania films deposited on FTO substrates. The results show that the film thickness increases with increasing the deposition time. It could be inferred from UV-Vis spectroscopy that increasing the thickness of deposited film causes higher absorbance at UV region. Also, increasing the deposition time from 1 to 5 min leads to increase in optical band gap of the deposited films.

scholarly journals Exploring the Impact of Early Decisions in Variable Ordering for Constraint Satisfaction Problems

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
José Carlos Ortiz-Bayliss ◽  
Ivan Amaya ◽  
Santiago Enrique Conant-Pablos ◽  
Hugo Terashima-Marín
Keyword(s):  
Constraint Satisfaction ◽  
Constraint Satisfaction Problems ◽  
Search Cost ◽  
High Quality ◽  
Simple Method ◽  
Variable Ordering ◽  
It Performance ◽  
The Cost ◽  
The Impact ◽  
Variable Ordering Heuristics

When solving constraint satisfaction problems (CSPs), it is a common practice to rely on heuristics to decide which variable should be instantiated at each stage of the search. But, this ordering influences the search cost. Even so, and to the best of our knowledge, no earlier work has dealt with how first variable orderings affect the overall cost. In this paper, we explore the cost of finding high-quality orderings of variables within constraint satisfaction problems. We also study differences among the orderings produced by some commonly used heuristics and the way bad first decisions affect the search cost. One of the most important findings of this work confirms the paramount importance of first decisions. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. We propose a simple method to improve early decisions of heuristics. By using it, performance of heuristics increases.

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